In a switching platform, frames arrive from source ports and must be transferred to appropriate destination ports. Transferring a frame from a source port to a destination port typically requires the participation of some central routing authority, such as a central processing unit. This participation can take a form where the central processing unit (CPU) must poll each port in turn, checking for possible frames to route. Furthermore, a switching platform may allow for a configuration that restricts the possible source ports to some maximum possible set. In such an instance, the CPU may spend unnecessary cycles polling ports which never produce a frame to route. These unnecessary cycles increase frame routing latency, which is a key metric of switch performance.
A need has arisen for a method and system which improves the operation of a central routing authority, such as a CPU, in routing a frame from a source port to a destination port.
A need exists for a method and system that avoids the requirement for the CPU to poll each port in sequence, to check for possible frames to route.
A further need exists for a method and system that avoids the need to spend unnecessary cycles in polling ports which will never produce a frame to route.
There is a need for a method and system that avoids the performance of unnecessary cycles during the polling of ports for the purpose of decreasing the frame routing latency.
A problem with SCSI is that it is not a switchable protocol. The fibre channel protocol, on the other hand, is a switchable protocol. Using fibre channel technology, it is possible to implement switches which direct data to the appropriate destinations.
A key metric of how well a switch operates is the speed with which it routes frames. Speed is one of the greatest advantages of fibre channel systems. The present invention reduces the amount of time it takes to route a frame and is therefore ideal for implementation in fibre channel systems. When any individual frame comes into a switch, the present invention requires less time for the switch to decide how to direct the individual frame.